[kh99]

You might be able to create a new plugin using hook showthread_query and code like:

$hook_query_fields .= " , DTO_garage_vehicle.* ";
$hook_query_joins .= " LEFT JOIN DTO_garage_vehicle ON (DTO_garage_vehicle.userid = post.userid) ";

Then in the postbit (or postbit_legacy) template use {vb:var post.year}, {vb:var post.make}, etc.

The above assumes that DTO_garage_vehicle has a userid field.